AER Benchmark Series User manual

Printed in U.S.A. 06/06/01
GF-107
OMM-0009_0A
Benchmark 2.0 Gas Fired Boiler
USER MANUAL
Used for Serial Numbers G-00-711 thru G-01-095
Benchmark
Series
Gas Fired
Boiler System
Condensing, Modulating
Forced Draft,
Natural Gas Fired, Hot Water Boiler
2,000,000 BTU/H Input

CONTENTS
i
GF-107 THE AERCO Benchmark 2.0 GAS FIRED BOILER
Operating & Maintenance Instructions
FOREWORD
Page
Section 1 SAFETY PRECAUTIONS----------------------------------1-1
1.1 Safety Warnings 1.3 Prolonged Shut-Down
1.2 Emergency Shut Down
Section 2 INSTALLATION PROCEDURES-------------------------2-1
2.1 Receiving the Unit
2.2 Unpacking
2.3 Installation
2.4 Gas Supply Piping
2.5 Electrical Supply
2.6 Mode of Operation and Field Control
Wiring
2.7 Aux. Contacts
2.8 Enable/Disable Interlock
2.9 Fault Relay Wiring
2.10 Flue Gas Vent Installation
2.11 Combustion Air
2.12 Unit Initial Fill
Section 3 CONTROL PANEL COMPONENTS and
OPERATING PROCEDURES-----------------------------3-1
3.1 The Control Panel
3.2 The Temperature Controller
3.3 The Primary Menu
3.4 The Secondary Menu
3.5 The Status Annunciator
3.6 The Combustion Safeguard
3.7 Water Level Test and Reset
3.8 On\Off Switch
3.9 Starting sequence
3.10 After Flame
3.11 Flame Test Jacks
3.12 Start \ Stop Levels
3.13 Auto Restarts
Switches
Section 4 INITIAL START-UP------------------------------------------4-1
4.1 Initial Start-Up requirements
4.2 Tools and Instrumentation for
Combustion Calibration
4.3 Combustion Calibration of Natural Gas
Unit
4.4 Combustion Calibration of Dual Fuel
Unit
4.5 Boiler Reassembly
4.6 Over-Temperature Limit Switch
Section 5 BOILER MODE of OPERATION-------------------------5-1
5.1 Indoor/Outdoor Reset Mode
5.2 Constant Setpoint Mode
5.3 4-20 ma Remote Setpoint Mode
5.4 4 to 20 ma Direct Drive Mode
5.5 Boiler Management System
5.6 Combination Control System
5.7 Using the Outside Air Sensor Feature

CONTENTS
ii
Page
Section 6 SAFETY DEVICE TESTING PROCEDURES---------6-1
6.1 Testing of Safety Devices
6.2 Gas Pressure Fault Test
6.3 Low Water Level Fault Test
6.4 Water Temperature Fault Test
6.5 Flame Fault Test
6.6 Air Pressure Fault Test
6.7 Purge Interlocks Fault Test
6.8 Safety Pressure Relief Valve Test
Section 7 MAINTENANCE REQUIREMENTS---------------------7-1
7.1 Maintenance Schedule
7.2 Spark Ignitor
7.3 Flame Detector
7.4 Combustion Calibration
7.5 Safety Device Testing
7.6 Burner
7.7 Exhaust Manifold and Combustion
Chamber
7.8 Shutting boiler down for and extended
period
7.9 Restarting after Prolonged Shutdown
Section 8 TROUBLESHOOTING-------------------------------------8-1
8.0 Low Gas Pressure
8.1 High Gas Pressure
8.2 Low Water Level
8.3 High Water Temperature
8.4 Lock Out Run Flame
8.5 Lock Out Run Air Pressure
8.6 System Fault Low Air Pressure or Purge
Interlocks
APPENDICES:
A. Temperature Controller Menus
B. Temperature Controller Quick Reference
Programming Guide
C. Temperature Sensor Resistance Chart
D. Indoor\Outdoor Reset Ratio Charts
E. Mode of Operation Factory Default Settings
F. Dimensional & Parts Drawings
G. Piping Drawings
H. Troubleshooting Flow Chart
WARRANTIES

FOREWORD
Foreword
The AERCO Benchmark boiler is a true industry advance that meets the needs of today's
energy and environmental concerns. Designed for application in any closed loop hydronic
system, the Benchmark's modulating capability relates energy input directly to fluctuating
system loads. The Benchmark's 15:1 turn down ratio and condensing capability offers extremely
high efficiencies and makes the Benchmark ideally suited for modern low temperature, as well
as, conventional heating systems.
Whether used in singular or modular arrangements the Benchmark offers the maximum
flexibility in venting with minimum installation space requirements. The Benchmark's advanced
electronics are available in several selectable modes of operation offering the most efficient
operating methods and energy management integration.
For service or parts, contact your local sales representative or AERCO INTERNATIONAL.
NAME:
ORGANIZATION:
ADDRESS:
TELEPHONE:
INSTALLATION DATE: _____________________________________________

SAFETY PRECAUTIONS
1-1
Chapter 1
1.1 WARNINGS & CAUTIONS
Installing or operating personnel MUST, at
all times, observe all safety regulations. The
following warnings and cautions are general
and must be given the same attention as
specific precautions included in these
instructions. In addition to all the
requirements included in this instruction
manual by AERCO, the installation of units
MUST conform with local building codes, or,
in the absence of local codes, ANSI Z223.1
(National Fuel Gas Code Publication No.
NFPA-54). Where ASME CSD-1 is required
by local jurisdiction, the installer must
conform to CSD-1.
Where applicable, the equipment shall be
installed in accordance with the current
Installation Code for Gas Burning
Appliances and Equipment, CGA B149, and
applicable Provincial regulations for the
class; which should be carefully followed inn
all cases. Authorities having jurisdiction
should be consulted before installations are
made.
WARNINGS!
MUST BE OBSERVED TO PREVENT
SERIOUS INJURY.
WARNING!
BEFORE PERFORMING
MAINTENANCE ON THE UNIT, SHUT
OFF GAS ELECTRIC TO THE UNIT.
WARNING!
THE EXHAUST VENT PIPE
OPERATES UNDER A POSITIVE
PRESSURE AND MUST BE
COMPLETELY SEALED TO PREVENT
LEAKAGE OF COMBUSTION
PRODUCTS INTO LIVING SPACES.
WARNING!
DO NOT USE MATCHES, CANDLES,
FLAMES, OR OTHER SOURCES OF
IGNITION TO CHECK FOR GAS
LEAKS.
WARNING!
FLUIDS UNDER PRESSURE MAY
CAUSE INJURY TO PERSONNEL OR
DAMAGE TO EQUIPMENT WHEN
RELEASED. BE SURE TO SHUT OFF
ALL INCOMING AND OUTGOING
WATER SHUTOFF VALVES AND
CAREFULLY DECREASE ALL
TRAPPED PRESSURES TO ZERO
BEFORE PERFORMING ANY
MAINTENANCE.
CAUTIONS!
Must be observed to prevent equipment
damage or loss of operating
effectiveness.
CAUTION!
Many soaps used for gas pipe leak
testing are corrosive to metals. The
piping must be rinsed thoroughly with
clean water after leak checks have been
completed.
CAUTION!
Do not use this boiler if any part has
been under water. Call a qualified
service technician to inspect and
replace any part that has been under
water.
NOTES:
Notes must be observed for proper
operating procedures & conditions.

SAFETY PRECAUTIONS
1-2
1.2 EMERGENCY SHUTDOWN
Should overheating occur or the gas supply
fail to shut off, manually shut off the gas
supply external to the boiler.
1.3 PROLONGED SHUTDOWN
After prolonged shutdown, it is
recommended that the startup procedures in
Section 4 and test procedures in Section 6
of this manual be performed, to verify
system-operating parameters. If there is an
emergency, turn off the electrical power
supply to the Aerco boiler and close the
manual gas valve located before the unit.
The installer is to identify the emergency
shut-off device

INSTALLATION
2-1
Chapter 2 - INSTALLATION
2.1 RECEIVING THE UNIT
Each Benchmark is shipped as a single crated
unit. The shipping weight is approximately 1650
pounds, and must be moved with the proper
rigging equipment for safety and to avoid
damages. The unit should be completely
inspected for shipping damage and
completeness at the time of receipt from the
carrier and before the bill of lading is signed.
NOTE:
AERCO is not responsible for lost or
damaged freight.
Each unit has a Tip-N-Tell indicator on the
outside of the crate. This indicates if the unit has
been turned on its side. If the Tip-N-Tell
indicator is tripped, do not sign for the shipment.
Note the information on the carrier’s paperwork
and request a freight claim and inspection by a
claims adjuster before proceeding. Any other
visual damage to the packaging materials
should also be made clear to the delivering
carrier.
2.2 UNPACKING
Carefully unpack the unit by removing the
packaging material. Take care not to damage
the unit jacket when cutting away packaging
materials. A close inspection of the unit should
be made to determine if there has been any
damage not indicated by the Tip-N-Tell. The
freight carrier should be notified immediately if
any damage is detected. The following
accessories come standard with each unit and
are packed separately within the unit’s’ packing
container or are factory installed on the boiler.
•Spare Spark Ignitor
•Spare Flame Detector
•ASME Pressure Relief Valve
•Ignitor Removal Tool (One per Site)
•Regulator Adjustment Tool (One per
Site)
•Condensate Drain Trap and Fittings
•A Gas Supply Pressure Regulator
When ordered, optional accessories may be
packed separately or with in the boiler shipping
container, or may be installed on the boiler. Any
standard or optional accessories shipped loose
should be identified and put in a safe place until
ready for installation or use
.
Figure 2.1
Boiler Clearances

INSTALLATION
2-2
2.3 INSTALLATION
The unit must be installed with the prescribed
clearances for service as shown in Figure 2.1.
The minimum clearance dimensions, required by
AERCO, are listed below. Local building codes
may require more clearance and take
precedence
Minimum clearances required:
Sides 24"
Front 24"
Rear 36"
Top 18"
All gas piping, water piping and electrical conduit
or cable must be arranged so that they do not
interfere with the removal of any cover, or inhibit
service or maintenance of the unit.
WARNING!
KEEP UNIT AREA CLEAR AND FREE
FROM COMBUSTIBLE MATERIALS AND
FLAMMABLE VAPORS AND LIQUIDS.
CAUTION!
While packaged on the shipping skid the
boiler must be moved by pallet jack or
forklift from the rear only.
2.3.1. SETTING THE UNIT
Lifting lugs are provided for moving the unit
when it has been removed from the shipping
skid (See Fig. 2.2). Remove the corrugated box
and wrapping material from the unit. Remove
the rear top panel from the unit to provide
access to the lifting lugs. Remove the four- (4)
lag screws securing the boiler to the shipping
skid. Lift the unit off the shipping skid and
position it on to the four-inch high mounting pad
(required) in the desired location. If anchoring
the unit, see the dimensional drawing in
appendix F for their location. USE ONLY THE
LIFTING LUGS TO MOVE THE UNIT.
In multiple unit installations, it is important to
plan the position of each unit. Sufficient space
for piping connections and future maintenance
requirements must be given. All piping must
include ample provision for expansion.
If installing a Combination Control, (CCP),
system, it is important to identify and place the
Combination Mode units in the proper physical
location. If these boilers are not properly located,
it will be necessary to reprogram them.
LIFTING LUGS
SHEET METAL OUTLINE
FRONT
BURNER
Figure 2.2
Lifting Lug Location
2.3.2 SUPPLY AND RETURN PIPING
The Benchmark 2.0 utilizes 4" 150# flanges for
the water system supply and return piping
connections. See appendix F for dimensional
data. The physical location of the supply and
return piping connections is on the rear of the
unit (See Fig 2.3 For Details).
Figure 2.3
Supply and Return Location
BOILER SUPPLY
(4"-150# FLG'D CONN.)
(4"-150# FLG'D CONN.)
BOILER RETURN

INSTALLATION
2-3
2.3.3 CONDENSATE PIPING
The Benchmark boiler is designed to condense
water vapor from the flue products and the
installation must have provisions for suitable
waste drainage or collection. A drain connection
provided on the exhaust manifold, (see Fig 2.6)
directs condensate from the exhaust manifold to
a 3/4 inch NPT condensate drain trap. The
condensate drain trap and associated fittings are
shipped loose and should be installed on the
exhaust manifold in rear of the unit. (See Fig.
2.6 for installation details.) Condensate drainage
from the condensate drain trap must be by
gravity to a nearby floor drain via a
polypropylene hose or suitable piping.
If a floor drain is not available, a condensate
pump can be used to remove the condensate to
drain. The maximum condensate flow rate is 11
GPH. The condensate drain trap, associated
fittings and drain line must be removable for
routine maintenance. Do not hard pipe.
2.4. GAS SUPPLY PIPING
The AERCO Gas Fired Equipment Gas
Components and Supply Design Guide (GF-
1030) must be consulted before any gas piping
is designed or started.
WARNING!
DO NOT USE MATCHES, CANDLES,
FLAMES OR OTHER SOURCES OF
IGNITION TO CHECK FOR GAS LEAKS.
CAUTION!
Many soaps used for gas pipe leak testing
are corrosive to metals. The piping must be
rinsed thoroughly with clean water after leak
checks have been completed.
NOTE:
All gas piping must be arranged so that it
does not interfere with removal of any
cover, inhibit service or maintenance, or
prevent access between the Unit and walls,
or another unit.
Figure 2.6
Condensate Drain Connection Location
The location of the 2" inlet gas connection is
located on the rear of the unit as shown in
Figure 2.7.
All pipes should be de-burred and internally
cleared of any scale or iron chips before
installation. No flexible connectors or non-
approved gas fittings should be installed. Piping
should be supported from floor, ceiling or walls
only and must not be secured to the unit.
A suitable piping compound, approved for use
with natural gas, should be used sparingly. Any
excess must be wiped off to prevent clogging of
components.
EXHAUST MANIFOLD
1/2"NPT CONDENSATE DRAIN CONN.
3/4" NPT EXHAUST GAS
CONDENSATE DRAIN CONN.

INSTALLATION
2-4
To avoid damage to the unit, when pressure
testing gas piping, isolate the unit from the gas
supply piping. At no time should there be more
than 14” W.C. to the unit. Leak test all external
piping thoroughly for leaks using a soap and
water solution or suitable equivalent. The gas
piping must meet all applicable codes.
2.4.1 GAS SUPPLY SPECIFICATONS
AND GAS SUPPLY REGULATORS
The maximum static pressure to the unit must
be no more than 14” W.C. Minimum operating
gas pressure is 7” W.C. when the unit is firing at
maximum input. Proper sizing of the gas supply
regulator in delivering the correct gas flow and
outlet pressure is mandatory. The gas supply
pressure regulator must be of sufficient capacity
volume to provide 2000 cfh while maintaining
the gas pressure at 7” W.C., for natural gas, and
should have no more than 1" droop from
minimum to full fire.
A Maxitrol RV-91 gas supply regulator is
supplied by AERCO and must be positioned as
shown in figure 2.7. Maximum gas pressure to
the RV-91 is 14" W.C. If the gas supply pressure
will exceed 14" W.C., a lock -up style regulator is
required up stream of the RV-91.
When installing the gas supply regulator(s),
union connections should be placed in the
proper locations to allow for maintenance.
The gas supply regulator must be properly
vented to outdoors. Consult the local gas utility
for exact requirements concerning venting of
supply gas regulators.
NOTE:
If a regulator other than the Maxitrol RV-91
supplied with the boiler is used it must be
capable or regulating 2,000,000 BTU/HR of
natural gas while maintaining 7” W.C. to the
boiler.
CAUTION!
A lockup style regulator must be used when
gas supply pressure exceeds 14” W.C.
2.4.2 MANUAL GAS SHUTOFF VALVE
A 2” manual gas shut-off valve is furnished with
each unit. The valve should be positioned as
shown in Figure 2.7 upstream of the supply
regulator in a readily accessible location.
2.4.3 IRI GAS TRAIN KIT
The IRI gas train is an optional gas train
required in some areas by code or for insurance
purposes. The IRI gas train is factory pre-piped
and wired.
Figure 2.7
Gas Supply Regulator and Manual Shut-Off
Valve Location
2.5 ELECTRICAL SUPPLY
The AERCO Gas Fired Equipment Electrical
Power Wiring Guide, (GF-2060), must be
consulted in addition to the following material
before wiring to the unit is started. The location
of the A.C. electrical wiring connnections are
inside the control box as shown in Figure 2.8.
NOTE:
All electrical conduit and hardware should
be installed so that it does not interfere with
the removal of any cover, inhibit service or
maintenance, or prevent access between
the unit and walls or another unit.
GAS SUPPLY:
SEE GF-2030 FOR
COMPLETE GAS
PIPING INSTALLATION
DETAILS

INSTALLATION
2-5
Figure 2.8
AC Input Terminal Location
2.5.1 ELECTRICAL REQUIREMENTS
The Benchmark boiler is available in one of the
three following electrical configurations:
220/1O/60 ---@ 20 amps
208-230/3O/60---@15 amps
Each Benchmark boiler must be supplied by a
dedicated electrical circuit. No other devices
should be on the same electrical circuit as the
BENCHMARK boiler. A means for disconnecting
AC power from the unit (such as a service
switch) must be installed near the unit for normal
operation and maintenance. All electrical
connections should be made in accordance with
the National Electrical Code and/or with any
applicable local codes.
For electrical power wiring diagrams, see the
Benchmark Electrical, Power Wiring Guide, GF-
2060. When wiring, conduit should be run from
the knockouts provided on the control box in
such a manner that it does not interfere with the
removal of any sheet metal covers (see figure
2.9 for knockout location).
2.6 MODE OF OPERATION and FIELD
CONTROL WIRING
The BENCHMARK Boiler is available in several
different modes of operation. While each unit is
factory configured and wired for a particular
mode, some field wiring may be required to
complete the installation. This wiring is typically
run to the Control Box located on the front of the
unit behind the removable Front Door (see Fig.
2.10). Field wiring for each particular mode of
operation is described in the following sections.
Figure 2.9
AC Power Knockout Locations
Figure 2.10
Control Wiring Terminal Location
2.6.1 CONSTANT SETPOINT MODE
No wiring connections other than electrical
supply connections are required for this mode.
Although fault monitoring or enable/disable
interlock wiring can be utilized (see sections 2.7
and 2.8).
TOP OF CONTROL BOX
TERMINAL BLOCK
LOWER PART OF CONTROL BOX
FIELD WIRING TERMINAL

INSTALLATION
2-6
Figure 2.11
Control Wiring Terminal Strip
2.6.2 INDOOR/OUTDOOR RESET MODE
This mode of operation increases supply water
temperature as outdoor temperatures decrease.
An outside air temperature sensor (AERCO PN
122790) MUST BE wired to the control wiring
terminals using a twisted shielded pair of 18-22
AWG wire (see Fig. 2.11). The cable shield is
connected only at the terminals provided at the
control wiring terminal strip located at the bottom
left hand corner of the control panel. The sensor
end of the shield must be left free and
ungrounded. There is no polarity in terminating
the sensor wires. When mounting the sensor, it
must be mounted on the north side of the
building in an area where the average outside
air temperature is expected. The sensor must be
shielded from the sun's direct rays, as well as
direct impingement by the elements. If a cover
or shield is used, it must allow free air
circulation. The sensor may be mounted up to
two hundred feet from the unit.
2.6.3 BOILER MANAGEMENT SYSTEM
MODE
When using an AERCO Boiler Management
System Panel, Model 168, the field wiring is
between the BMS Panel and each unit’s control
wiring terminal (see Fig. 2.11). A twisted
shielded pair of 18 to 22 AWG wire must be
utilized for the connections. Connections are
made from the AERCO boiler management
system to terminals 2 and 3 of the boiler's
control terminal wiring strip. Polarity must be
maintained and the shield is to be connected
only at the AERCO boiler management system
and must be left floating at the boiler. For further
wiring instructions see the GF-108, BMS
Operations Guide.
2.6.4 4 to 20mA REMOTE SETPOINT and
DIRECT DRIVE MODES
The BENCHMARK boiler can be controlled with
a 4-20mA signal from an energy management
system or an external controller. The 4-20mA is
linearly mapped to a 40-220oF set point or to 0
to 100% input.
All supplied 4-20mA signals must be a floating
(ungrounded) signal. Connections between the
4-20mA source and the unit's control wiring
terminals must be made using a twisted shielded
pair of 18-22 AWG wire such as Belden 9841
(see Fig. 2.11). The shield is connected only at
the terminal provided on the control wiring
terminals. The shield must be left free and
ungrounded at the source end. Polarity must be
maintained when connecting the wires.
2.6.5 COMBINATION MODE
With a Combination Mode unit, field wiring is
between the unit’s control wiring terminals, the
CCP (Combination Control Panel), and the BMS
(Boiler Management System). The wiring must
be done using a shielded twisted pair of 18- 22
AWG wire and polarity must be maintained. For
further instructions and wiring diagrams, consult
the GF-108, Boiler Management System
Operations Guide and the CCP-1 data sheet.
2.7 AUXILLIARY CONTACTS
Each boiler is equipped with a SPDT relay that
is powered when there is a demand for heat.
The relay is provided for the control of auxiliary
equipment such as pumps and louvers. Its
contacts are rated for 120 VAC @ 5 amps (see
figure 2.11 terminals 5,6 and 7 for wiring
location).
2.8 INTERLOCKS
The Benchmark boiler offers two interlock
circuits for interfacing with energy management
systems and auxiliary equipment such as pumps
or louvers (see figure 2.12). These interlocks are
located on the inside of control panel door and
are labeled Enable/Disable and Delayed
Interlock. Both interlocks, described below, are
factory wired closed and must be closed,
(jumped), to allow the unit to fire.
2.8.1 DELAYED INTERLOCKS
The delayed interlocks are typically used in
conjunction with the auxiliary relay described
above in section 2.7. This interlock circuit is
located in the purge control section of the start

INSTALLATION
2-7
string. It therefore does not need to be closed for
the boiler start sequence to begin but does need
to be closed within 30 seconds for the boiler to
fire. The delayed interlock is usually connected
to the proving device of the auxiliary equipment
started by the auxiliary relay. These interlocks
are labled Delayed Int'lock and their location is
on the inside of the control panel door. The
interlock circuit is 120 VAC, and comes factory
pre-wired closed. See figure 2.12.
2.8.2 REMOTE ENABLE/ DISABLE
An enable/disable circuit is provided for remote
start and stop. The circuit is labeled
Enable/Disable and is located on the inside of
the control panel door. The circuit is 120 VAC,
and comes factory pre-wired closed (jumped).
See figure 2.12.
2.9 FAULT RELAY WIRING
The fault relay contains a set of normally open
dry contacts, rated for 5 amps at 120 VAC and 5
amps at 30 VDC that close on any fault
condition. The relay will remain energized until
the fault is cleared and the CLEAR button is
depressed. The fault relay connections are
shown in Figure 2.11.
Figure 2.12
Interlock Wiring
2.10 FLUE GAS VENT INSTALLATION
The AERCO Venting and Combustion Air Guide,
GF-2050, must be consulted before any flue gas
vent or inlet air venting is designed or installed.
U/L listed, positive pressure, watertight vent
materials as specified in AERCO’s GF-2050,
must be used for safety and code compliance.
Because the unit is capable of discharging low
temperature exhaust gases, the flue must be
pitched back to the unit a minimum of 1/4" per
foot to avoid any condensate pooling and to
allow for proper drainage.
The combined pressure drop of vent and
combustion air systems must not exceed 140
equivalent feet of 8”’ inch ducting. Fittings as
well as pipe lengths must be calculated as part
of the equivalent length.
For a natural draft installation the draft must not
exceed -0.25”/+0.25" W.C. These factors must
be planned into the vent installation. If the
maximum allowable equivalent lengths of piping
are exceeded, the unit will not operate properly
or reliably.
2.11 COMBUSTION AIR
The AERCO Venting and Combustion Air Guide,
GF-2050, MUST be consulted before any flue or
combustion supply air venting is designed or
started. Combustion air supply is a direct
requirement of ANSI 223.1, NFPA-54, and local
codes. These codes should be consulted before
a permanent design is determined.
The combustion air must be free of chlorine,
halogenated hydrocarbons, or other chemicals
that can become hazardous when used in gas-
fired equipment. Common sources of these
compounds are swimming pools, degreasing
compounds, plastic processing and refrigerants.
Whenever the environment contains these types
of chemicals, combustion air must be supplied
from a clean area outdoors for the protection
and longevity of the equipment.
The Benchmark is UL listed for 100% sealed
combustion and can be ordered with a sealed
combustion option, or can be installed using
room air as long as there is an adequate supply.
(See section 2.11.3 for more information
concerning sealed combustion air.)
If the sealed combustion air option is not being
used, an inlet screen will be attached at the
blower suction and the knockout at the top of the
unit will be and should remain in place.
The more common methods of supplying
combustion air are outlined below. For more
information concerning combustion air, consult
the AERCO GF-2050, Venting and Combustion
Air Guide.
2.11.1 COMBUSTION AIR FROM
OUTSIDE THE BUILDING
Air supplied from outside the building must be
provided through two permanent openings. Each
opening must have a free area of not less than
one square inch for each 4000 BTU boiler input.
The free area must take into account restrictions
such as louvers and bird screens.

INSTALLATION
2-8
2.11.2 COMBUSTION AIR FROM INSIDE
THE BUILDING
When combustion air is provided from within the
building, it must be supplied through two
permanent openings in an interior wall. Each
opening must have a free area of not less than
one square inch per 1000 BTUH of total boiler
input. The free area must take into account any
restrictions such as louvers.
2.11.3 SEALED COMBUSTION
The BENCHMARK boiler is UL listed for 100%-
sealed combustion and can be ordered with a
sealed combustion option or without. Units
ordered in the sealed combustion configuration
will come with an air inlet assembly installed on
the blower. The knockout at the top of the boiler
must be removed and the combustion air
ductwork must be attached to the 6" x 8" adapter
that is provided just below the knockout.
'In a sealed combustion air application, the
combustion air ducting pressure losses must be
taken into account when calculating the total
maximum allowable venting run. See the
AERCO Venting and Combustion Air Guide, GF-
2050. When using the boiler in a sealed
combustion air configuration, each unit must
have a minimum 8" diameter connection at the
unit.
2.12 UNIT INITIAL FILL
Before filling the unit’s shell for the first time,
blow out all the connecting water and gas piping
and check thoroughly for leaks. Rinse all
soapsuds from the gas piping with clean water.
Do not allow water to get on the control panel or
electrical connections. Check that all installation
procedures have been completed before filling
the unit.
The following steps should be followed when
filling the unit:
1. Close the unit’s drain valve.
2. Open the system return and supply valves to
the boiler.
3. Make certain that the system pressure
reducing fill valve is open to replenish
pressure in the system as the unit fills.
4. Observing the pressure/temperature gauge,
supplied with the unit, allow pressure to
slowly build up in the unit.

CONTROL PANEL OPERATING PROCEDURES
3-1
Chapter 3 - CONTROL PANEL OPERATING PROCEDURES
The following is a guide to the operation of the
control panel. Initial start-up of this unit must be
performed by factory trained start-up personnel.
Operation prior to initial start-up by factory
trained personnel will void the warranty.
CAUTION:
All initial installation procedures must be
satisfied before attempting to start the unit.
WARNING:
DO NOT ATTEMPT TO DRY FIRE THE
BOILER. STARTING THE UNIT WITHOUT
A FULL WATER LEVEL CAN SERIOUSLY
DAMAGE THE UNIT AND MAY RESULT IN
PERSONNEL INJURY OR PROPERTY
DAMAGE. THIS SITUATION WILL VOID
ANY WARRANTY.
3.1 THE CONTROL PANEL
The Benchmark Control Panel has been
designed to provide the operator with all the
necessary information required to effectively
operate and troubleshoot this unit. A 4amp
circuit breaker is provided to protect the control
circuits. There are six separate accessible
controls or displays available to the operator,
(see Fig. 3.1). These are:
1. The Temperature Controller
2. The Annunciator & Function Switches
3. Circuit Breaker
4. The Combustion Safeguard Controller
5. Water Level Test and Reset Switches
6. On/Off Switch
7. Fault Indicator Light
The following sections will describe the above
components in more detail.
WARNING
CONTROL BOX INTERNALS MUST NOT
BE SERVICED OR ACCESSED BY
OTHER THAN FACTORY CERTIFIED
SERVICE TECHNICIANS. ALL CONTROL
BOX INTERNALS HAVE THE CAPABILITY
OF HOLDING AN ELECTRICAL VOLTAGE
OF 220 AND 120 VOLTS AC.
Figure 3.1
Front Panel Controls Location
COMBUSTION SAFEGUARD
CONTROLLER
WATER LEVEL TEST/
RESET SWITCHES
ON/OFF SWITCH
ANNUNCIATOR &
FUNCTION SWITCHES
FAULT INDICATOR
TEMPERATURE
CONTROLLER
CIRCUIT BREAKER

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3-2
3.2 THE TEMPERATURE CONTROLLER
The temperature controller is a PID
programmable controller that utilizes feedback
information to accurately maintain a desired set
point. It is the primary source for programming
and viewing operating parameter settings. It
plays a part in the start sequence and includes
other features such as:
•LED display
•5 indicator status lights
•3 menu levels
•RS-485 communications capability
3.2.1 LED DISPLAY
The display consists of a two line, four character
seven segment LED’s, (see Fig. 3.2). When an
operating parameter is chosen to be changed or
looked at, the lower LED display indicates the
parameter being looked at in the form of a code.
The upper display indicates the parameter’s
value. For a complete listing of the operating
parameters see Appendix A of this manual.
3.2.2 INDICATOR STATUS LIGHTS
The first LED indicator light, “MAN” indicates
whether the controller is in auto or manual
mode, (see Fig 3.2). When lit, the controller is in
manual mode and the operator is responsible for
operation of the unit. When the LED is not lit, the
controller is in auto mode. In auto mode the
controller is operating the unit from signals
generated by sensors located on the unit or in
the system, or by signals from an energy
management system.
The second LED, “REM”, designates whether
the controller is being controlled locally or
remotely, (see Fig. 3.2). When lit the controller is
in remote mode and it can accept commands
from an external source. When this LED is not
lit, the controller is in local mode and it will
respond to its current internal settings are. All
external commands are ignored.
The third LED, “Demand for Heat " indicates
whether the temperature controller's internal
start relay is open or closed (see Fig. 3.2). The
start relay is part of the start sequence, closing
when the control signal reaches 25% or higher.
This lights the "Demand for Heat" LED and
begins the combustion process. The start relay
opens when the control signal is 19.9% or lower,
shutting the "Demand for Heat" LED and
stopping the combustion process.
The last two LED’s, “oF” and “oC”, indicate
whether the temperature displayed is
°Fahrenheit or °Celsius, (see Fig. 3.2).
NOTE:
When the temperature controller is displaying in
oC only the temperature being displayed is
affected. All other values remain in oF.
3.2
Temperature Controller Operating Status Lights
3.2.3 MENU LEVELS
The temperature controller has two menu levels
that are operator accessible for programming
the unit functions and parameters. These are the
Primary and Secondary menus:
To change from the primary menu to the
secondary menu, simultaneously depress the 
arrow key and ENTER button. To change from
the secondary to the primary menu
simultaneously press the ⇓arrow key and the
MENU button.
To scroll through a menu, depress the MENU
button. To change a parameter scroll through
the menu until the desired parameter is
indicated on the controller’s lower LED display.
Then use the and arrow keys to change the
parameters value. Once a parameter’s value
has been changed the ENTER key must be
depressed for the change to be recognized by
the controller. Leaving the desired parameter
without entering the new value will result in that
parameter value defaulting back to the previous
value. Detailed descriptions and instructions for
accessing each menu parameter are listed
within this section. For more data concerning the
minimum and maximum range, and factory
defaults of menu parameters, see Appendix E of
this manual. Each menu level is described
below.

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3-3
3.3 THE PRIMARY MENU
The primary menu is the default menu. When in
another menu level and there is no activity for 5
minutes the temperature controller will default
back to the primary menu. The Primary menu
allows the operator access to the following
temperature controller parameters:
Code
Meaning
tout
Outlet water temperature.
pct
Firing rate percentage.
Setp
Desired set-point temperature.
Auto Automatic controlling mode ON or
OFF.
3.3.1 OUTLET TEMPERATURE (tout)
Outlet temperature is the actual outlet water
temperature of the unit. To access outlet
temperature press the MENU button until (tout)
is displayed in the lower LED. The variables
under this feature may not be manually
changed. Fig. 3.3 below shows an outlet
temperature of 120º F
3.3
Outlet Temperature Display
3.3.2 FIRING RATE PERCENTAGE (Pct)
Percentage of firing rate is a number, in percent,
that is directly related to the input BTU’s of the
unit. For instance a 50% firing rate equals
approximately 1,000,000 BTU gas input while a
75 % firing rate equals approximately 1,500,000
BTU gas input and so on.
CAUTION:
Do not leave the unit unattended while in
the manual mode of operation.
WARNING:
WHEN SWITCHING FROM AUTO TO
MANUAL MODE, THE UNIT WILL
CONTINUE TO OPERATE AT THE SAME
FIRING RATE PERCENTAGE AS WHEN
THE UNIT WAS IN AUTO MODE.
To access the firing rate percentage, press the
MENU button while in the primary menu until
(Pct) is displayed in the lower LED. While in
manual mode, (see section 3.3.4); use the or
arrow key to increase or decrease the
percentage of firing rate. Press the ENTER
button to accept the desired change. Figure 3.4
shows the temperature controller displaying a
100% firing rate.
Figure 3.4
Percent of Firing Rate Display
3.3.3 SETPOINT (Setp)
Setpoint is the desired outlet water temperature
that is to be maintained by the unit when in
automatic mode. Fig 3.5 shows the controller
with a setpoint of 120º F.
To access the unit’s setpoint press the MENU
button until (Setp) is displayed in the lower LED.
To increase or decrease the unit’s setpoint press
the or arrow keys. Press the ENTER button
to accept the change.
3.5
Setpoint Display
3.3.4 AUTOMATIC / MANUAL (Auto)
When set to automatic mode the controller is
receiving and processing inputs from
temperature sensor(s) located externally or on
the unit. The controller uses these inputs to
automatically decrease or increase the firing rate
to match the load.

CONTROL PANEL OPERATING PROCEDURES
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3-4
In manual mode, the controller no longer
automatically controls the firing rate of the unit. It
is up to the operator to control the outlet
temperature and firing rate. Manual mode is
commonly used for service and troubleshooting
the unit. All safety controls remain functional
whether the controller is in automatic or manual
mode.
To place the controller in automatic mode press
the MENU button until (Auto) is displayed in the
lower LED.
Now press the or arrow keys until ON is
displayed in the upper LED (see fig 3.6). Press
the enter button to accept the change. The MAN
LED should not be lit.
3.6
Auto/ Manual Display with Auto On
To place the temperature controller in manual
mode, press the or arrow keys until OFF is
displayed in the upper LED. (See Fig 3.7). Press
the enter button to accept the change. The MAN
LED should now be lit.
3.7
Auto/Manual Display with Manual On
3.4 THE SECONDARY MENU
The secondary menu is used to set temperature
control parameters. It is necessary to access
this menu when setting PID values or changing
the unit mode of operation.
To access the secondary menu, press the 
arrow key and ENTER simultaneously. To scroll
through the menu press the MENU button.
The secondary menu allows access to the
following temperature control features:
Func
Mode of 0peration
REFT
Building reference
temperature
RR
Reset Ratio
OSAT
Outside air sensor
feature
Oat
Maximum outside air
temperature that unit
is enabled to run
LLT
Low temperature
alarm setpoint
HLt
High temperature
alarm setpoint
Pb1
Proportional Band
Int
Integral Rate
Drt
Derivative Time
Addr
Controller address
for external
communication
Lore
Local/ remote status
of the control
For a complete explanation of the secondary
menu parameters see Appendix A of this
manual.
3.5 STATUS ANNUNCIATOR
The status annunciator consists of the
annunciator circuit board, the front panel LCD
display, and four function switches. Figure 3.8
show the location of the LCD and four function
switches. The annunciator circuit board is the
interface between the LCD display and the
combustion safeguard system. It monitors the
unit during every phase of operation and
displays start sequence and fault messages.
The function switches are used to reset the
annunciator and gain access to the
annunciator’s three function menus.

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3-5
Figure 3.8
Annunciator Function Switches and LCD Display
The status annunciator only monitors the boilers
control system. If any portion should fail, the
boiler will still operate with no adverse effects.
3.5.1 ANNUNCIATOR FUNCTION
SWITCHES and DISPLAYS
The Annunciator has three function displays that
are available to the operator. These are the
MAIN, the CYCLES, and the SET DATE
displays. These displays are accessed using the
four membrane switches located directly under
the LCD display on the front of the control panel.
They are labeled CLEAR, , , and AUX.
The MAIN display is used during normal
operation of the unit. In the MAIN display, start
sequence and fault messages can viewed. To
return to the MAIN display from any other
display, simultaneously press CLEAR and the 
arrow key. To reset the MAIN display after a
fault has occurred press the CLEAR button.
The CYCLES display indicates the date and
time, and the number of cycles the unit has
started since it was reset. When in the CYCLES
display only the number of cycles can be reset.
To reset the number of cycles to 0,
simultaneously press the , and arrow keys
and hold them for approximately four seconds.
In the SET DATE display, both the time and date
are displayed and can be changed.
To access the SET DATE display, press the
CLEAR button while in the CYCLES display.
Continue pressing the CLEAR button to move
through the SET DATE display fields. Use the 
and arrow keys to set the date and time.
The following table shows the messages
displayed after accessing the CYCLES and SET
DATE displays.
# CYCLES =
“DATE” “TIME”
The number of times
the controller has
completed it’s start
cycle, and the time
and date of the last
reset
SET DATE:
“DATE” “TIME”
Displays and allows
setting of the date
and time
3.5.2 ANNUNCIATOR FAULT
MESSAGES
The following table lists the Annunciator MAIN
display fault messages and their meanings.
MESSAGE
MEANING
RESET MAIN
POWER
AC power has been
interrupted. Power must
be shut off for 20
seconds then restored
to reset the display.
HIGH WATER
TEMP
The unit has locked out
due to the outlet water
temperature exceeding
the high temperature
limit setting.
LOW GAS
PRESSURE
The unit has tripped
due to low gas
pressure.
HIGH GAS
PRESSURE
The unit has tripped
due to high gas
pressure
LOW WATER
LEVEL
The shell water level is
below the probe level.
INTERLOCK
OPEN
The interlock terminals,
in the relay box, are not
closed.
PURGE INTLK
OPEN
The proof of closure or
the purge switch did not
prove closed during the
start sequence.
LOW AIR FLOW
The airflow switch did
not prove closed during
the start sequence.
SYSTEM FAULT
PURGE
INTERLOCKS
The proof of closure or
purge switch did not
prove closed 45
seconds after the unit
attempted to start.
SYSTEM FAULT
LOW AIR
PRESSURE
The air pressure switch
did not prove closed 45
seconds after the unit
attempted to start.
FLAME FAULT
Flame did not prove at
FAULT
CLEAR
AUX
MODE
ON
ANNUNCIATOR DISPLAY
ANNUNCIATOR FUNCTION SWITCHES

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8/1/99
3-6
DURING
IGNITION TRIAL
the end of the trial for
ignition period.
LOCKOUT RUN
AIR FLOW
The air pressure switch
opened after flame was
proven.
LOCKOUT RUN
FLAME
Flame signal was lost
after flame was proven.
LOCKOUT RUN
The combustion
safeguard is locked out.
3.5.3 ANNUNCIATOR START
SEQUENCE MESSAGES
The following table lists the annunciator MAIN
display start sequence messages.
STANDBY
The unit is in standby
mode waiting for a call
for heat
PURGING
The unit is in the 7-sec.
purge.
IGNITION TRIAL
The unit is in 10 second
ignition position,
attempting to light the
burner
FLAME PROVEN
The unit has
established flame and
is firing.
3.6 THE COMBUSTION SAFEGUARD
The Combustion Safeguard is responsible for
monitoring the safety components during the
start sequence and after flame is established. It
is also responsible for the timing of the start
sequence, including the purge and ignition
cycles.
The combustion safeguard is located in the
bottom of the control panel as shown in Figure
3.9. There are five status LED’s that indicate the
status of operation. These lights are redundant
to messages displayed by the annunciator. and
are useful as a double check on the annunciator.
The table below defines the function of each
LED’s. A reset button located on the combustion
safeguard is used to reset it after a lockout. The
combustion safeguard will shut the unit down if
one of the following occurs:
DESCRIPTION
FUNCTION
POWER
Lights when the limit string
is satisfied and there is a
call for heat.
PILOT
Lights when the air flow
circuit is satisfied.
FLAME
Lights during the trial for
ignition period.
MAIN
Lights once flame has
been detected.
ALARM
This lights when the
controller is in a
LOCKOUT condition.
3.9
Combustion Safeguard Status Indicator LED
Location
Note:
After resetting the combustion safeguard
the Annunciator must also be reset using
the CLEAR button.
3.7 WATER LEVEL TEST and RESET
SWITCHES
The water level switches are located on the left
side of the control box (see Fig. 3.10). When
depressed, the TEST switch simulates a low
water level condition by breaking the connection
between the water level probe and the sensing
circuitry. To test the low water level circuitry
depress the test switch for 3 seconds. The unit
should fault resulting in the red fault light blinking
and the LED display showing LOW WATER
LEVEL.
Note:
Only water level circuitry is tested during the
above test. The water level probe is not
tested. To determine if the probe is
functioning properly, the water level must be
reduced below the level of the probe.
To reset the unit, depress the water level reset
switch, the annunciator CLEAR button, and if
necessary, the reset button on the combustion
safeguard.